The present invention relates generally to heart wires and leads, and more particularly to temporary bipolar heart wires and leads for pacing, defibrillating and monitoring.
Unipolar and bipolar surgically implanted temporary heart wires are well known in the art, some examples of which may be found in the issued U.S. Patents listed in Table 1 below.
All patents listed in Table 1 hereinabove are hereby incorporated by reference herein in their respective entireties. As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description of the Preferred Embodiments and claims set forth below, many of the devices and methods disclosed in the patents of Table 1 may be modified advantageously by using the teachings of the present invention.
Surgically implanted temporary heart wires for use as heart pacer and monitoring electrodes are well known in the medical profession. In general, such a heart wire is constructed of a number of fine, stainless steel wires twisted together to form a single, flexible, multifilament electrode wire. The major portion of the wire is typically insulated with a polyethylene, polytetrafluoroethylene, silicone, nylon, or other suitable electrically nonconductive and biocompatible materials, with a short length of wire at either end left uninsulated.
To one uninsulated end of such an electrode wire there is generally attached by swaging or other means a fine curved needle for piercing the heart tissue to place the uninsulated end of the electrode in the myocardium or epicardium. At the other end of such an electrode wire there is generally affixed a Keith-type cutting needle for piercing the thoracic wall to lead the electrode to an outer point for connection with the pacemaker. Once the electrode has been properly positioned, the curved needle and the Keith-type needle are typically clipped off and the uninsulated end of the electrode is ready for attachment to a pacemaker or monitoring device.
Some prior art unipolar heart wires have break-away Keith-type needles attached to their proximal ends, where no clipping is required to remove the needle from the heart wire. Other prior-art Keith-type breakaway needles require the use of, or most preferably employ, an external adapter or transition box for breaking the needle in the appropriate location and facilitating attachment of electrical conductors in the lead to an external electrical apparatus. See, for example, the bipolar heart wire and corresponding external connector disclosed in U.S. Pat. No. 5,241,957, where the external connector is required to establish electrical connection between an EPG or PSA and the heart wire.
Many known heart wires are characterized in having one of the two following disadvantages. First, when some known unipolar heart wires are used in applications requiring two electrodes, two different, separate heart wires must be attached to the heart in two separate procedures. Attaching two such heart wires consumes valuable time at a critical stage in heart surgery. Second, when some known bipolar heart wires are used, the needle attached to the proximal end of the heart wire for piercing the transthoracic wall must be clipped off with a scissors or other tool, and pin connectors must be attached to the resulting bare separate wires for establishing electrical connection to an external pacemaker or external electrical apparatus. These steps of needle removal and wire attachment are separate, time consuming acts, and also occur at a critical stage in heart surgery. Moreover, upon repeated attachment, removal and reattachment, the ends of the stainless steel wire may fray and become difficult to work with.
What is needed is a heart wire that attaches easily and quickly to the heart but which also has convenient, easy-to-use connectors disposed between the proximal end of the heart wire and an external pulse generator (EPG), pacing system analyzer (PSA), defibrillator or other such external electrical apparatus. Most preferably, the heart wire should not require substantial electrical or mechanical manipulations by the surgeon, should be comfortable to the patient, and should establish secure and reliable electrical contacts. Finally, the heart wire should be reasonably economical to manufacture.
The present invention has certain objects. That is, the present invention provides solutions to problems existing in the prior art. It is an object of the present invention to provide a surgical electrode having a needle, the sharpened proximal end of which can be removed without cutting. It is a further object of this invention to provide a surgical electrode which is quickly and easily attached to an external electrical apparatus after the sharpened end of the needle has been removed. It is yet a further object of this invention to provide surgical electrodes having electrical connecting means adapted for specific electrical devices.
The present invention has certain advantages. More particularly, the heart wire of the present invention: (a) reduces patient trauma; (b) reduces the number of puncture sites in the myocardium or epicardium; (c) reduces the number of puncture sites in the thorax; (d) is easy to use; (e) permits two electrodes to be implanted quickly during a critical stage of heart surgery; (f) has electrodes spaced a predetermined optimal distance apart for sensing and pacing applications; (g) attaches to external pacemakers, defibrillators, monitoring equipment and other external electrical apparatus quickly, easily, securely and reliably; (h) does not require lead wires to be clipped with scissors; (i) requires no use of an external, separate adapter or transition box for separating or breaking the needle from the connectors; (1) requires no use of an external, separate adapter or transition box for establishing electrical connection between the electrodes and an external electrical apparatus; (k) prevents the distal ends of electrode wires from becoming frayed; (l) has fewer parts than many prior art heart needles; (m) is less expensive to manufacture; (n) helps reduce health care costs, and (o) increases patient safety owing to shortened implantation times and quicker connection to external pacing, defibrillating or monitoring equipment.
The heart wire and needle of the present invention have certain features, including one or more of the following: (a) a chest needle having a pointed or proximal end and a blunt or distal end, the blunt end being breakingly, snappingly, crimpingly, compressionally, slidingly, elastically, glueingly, viscously, vacuumingly or otherwise attached separably to the proximal ends of at least two connectors; (b) at least two connectors that upon being separated from the blunt end of the needle form pins or other structures suitable for fitting in or otherwise appropriately engaging an external connector configured to receive the connectors, where the external connector is attached to an external electrical apparatus for monitoring, pacing or defibrillating the heart; (c) a curved, straight or otherwise shaped needle disposed at the distal end of the heart wire that is suitable for piercing the myocardium or epicardium, and (d) two or more electrodes located between the distal and proximal ends of the heart wire for pacing, defibrillating or monitoring the heart, the electrodes being formed of exposed portions of bare wire, wherein overlying insulation has been removed.
In one preferred embodiment, the present invention is a temporary bipolar lead having a proximal and a distal end, and comprises a chest needle at its proximal end, the needle having a proximal pointed end and a distal blunt end attached to at least two connectors by a weakened zone. At least two pacing, sensing or defibrillating proximal and distal electrodes are disposed near the distal end of the lead, and a coil affixation member may optionally be formed by one of the electrodes. The two or more electrodes are preferably formed of bare wire electrically and mechanically connected to respective electrical conductors. The proximal electrode is most preferably formed of a portion of bare wire. The distal ends of the at least two electrical conductors form the electrodes, and also extend between the electrodes and the connectors.
Other objects, features, advantages and embodiments of the present invention will become apparent upon reading the detailed description and the claims.